ContactManager sample on Tomcat

I'm tring to deploy the FDS ContactManager sample using Tomcat 5.5. I installed and configured jotm 2.0 as described here:

http://www.silver-island.com/arts/flex/FDS2.0_on_Tomcat/contact_manage r_2.html

but when browsing contactmgr.mxml I still get this message "Unable to access UserTransaction in DataService". Any idea what is wrong here?